Development of new experimental models to understand the genetic basis of allergic bronchopulmonary aspergillosis

Project Background

Aspergillus fumigatus is an opportunistic pathogen which can cause pulmonary infection in immunocompromised individuals. While exposure to airborne Aspergillus spores is universal, allergic bronchopulmonary aspergillosis (ABPA) only manifests in patients with defective airway epithelial barrier function, such as asthmatics. However, less than 2% of asthma patients exposed to spores contract ABPA suggesting a genetic risk factor is involved in the pathogenesis of this disease. In ABPA research, transgenic mice expressing human genes are exposed to multiple low doses of Aspergillus spores to functionally validate the effect of the human gene on the development of ABPA.

Why we funded it

Through this Training Fellowship Dr Gago aims to replace transgenic mice used to investigate the genetic basis of ABPA pathogenesis with a human in vitro cellular model.

More than 10,000 publications about aspergillosis, asthma and allergy using mouse models have been published since 2000. To gain statistical significance, approximately nine mice are needed per experimental group resulting in the use of ~7,500 mice per annum. Mouse models used in these studies are classified as severe, as they entail the development of severe lung disease and mild-to-moderate respiratory distress. Dr Gago estimates that the Manchester Fungal Infection Group can replace over 50% of their animal use with the proposed in vitro models, with over 200 mice replaced in Dr Gago’s studies alone.

Research methods

Dr Gago and colleagues in the Manchester Fungal Infection Group have identified gene variants in ABPA patients that may contribute to the development of ABPA. During her fellowship, Dr Gago aims to edit the genome of bronchial epithelial cells and macrophages to introduce the identified mutations. These cells will then be challenged with Aspergillus spores to evaluate the immune response to Aspergillus exposure in the genetic context of ABPA. The role of the epithelial cells in mobilising the macrophages will be established by analysing the cytokine profile after exposure to Aspergillus spores. The results from these in vitro studies will then be validated using primary cultures of nasal brush and blood samples from patients with relevant ABPA genetic variants.